In order to use ultracapacitors in hybrid and electric vehicles applications, this study deals with their modeling and with ageing quantification during power cycling with high current levels. After introducing the ultracapacitors as peak power source in HEV, their physical principles and technological aspects are presented. Then, their electric behavior is investigated thanks to the specifications of well adapted test procedures and experimental test bench. We have focused on the dynamic behavior with high current levels of charge/discharge. Therefore, the obtained results are discussed and an equivalent electric model is proposed. The temperature effect on the electric parameters is quantified and introduced in the electric model. After that, a thermal model is identified and coupled to the electric one, allowing the estimation of the hot spot temperature. Therefore, the ultracapacitors self-heating and the thermal steady state can be predicted and validated experimentally. Finally, ageing study is made based on power cycling tests. Current profiles and test conditions are specified for ageing acceleration. The power cycling is interrupted by periodic characterization procedures. So, the obtained results were presented and discussed. We have focused on the changes of electric parameters, in particular the effect of the current shape, its rms value, and the rest time for characterization.
